Are humans hard-wired to be ruthlessly
competitive or supportive of one another?

The behavior of our ape relatives, known as
peaceful vegetarians, once bolstered the view that our actions could not be
traced to an impulse to dominate. But in the late 1970s, when chimpanzees were
discovered to hunt monkeys and kill each other, they became the poster boys for
our violent origins and aggressive instinct.

'Ardi'
Fossil Altering Ideas on Human Evolution

The skeleton of Ardipithecus ramidus, an ancient
fossil dubbed "Ardi," is radically changing our ideas about mankind's
origins. Kent State University's C. Owen Lovejoy says Ardi shows our ancestors
were more like us and less like chimps. WSJ's Robert Lee Hotz reports.

I use the term "boys" on
purpose because the theory was all about males without much attention to the
females of the species, who just tagged along evolutionarily. It was hard to
escape the notion that we are essentially "killer apes" destined to
wage war forever.

Doubts about this macho origin myth have
been on the rise, however, culminating in the announcement this past week of
the discovery of a fossil of a 4.4 million year old ancestor that may have been
gentler than previously thought. Considered close to the last common ancestor
of apes and humans, this ancestral type, named Ardipithecus ramidus (or
"Ardi"), had a less protruding mouth equipped with considerably
smaller, blunter canine teeth than the chimpanzee's impressive fangs. This
ape's canines serve as deadly knives, capable of slashing open an enemy's face
and skin, causing either a quick death through blood loss or a slow one through
festering infections. Wild chimps have been observed to use this weaponry to
lethal effect in territorial combat. But the aggressiveness of chimpanzees
obviously loses some of its significance if our ancestors were built quite
differently. What if chimps are outliers in an otherwise relatively peaceful
lineage?

Consider our other close relatives:
gorillas and bonobos. Gorillas are known as gentle giants with a close-knit
family life: they rarely kill. Even more striking is the bonobo, which is just
as genetically close to us as the chimp. No bonobo has ever been observed to
eliminate its own kind, neither in the wild nor in captivity. This slightly
built, elegant ape seems to enjoy love and peace to a degree that would put any
Woodstock veteran to shame. Bonobos have sometimes been presented as a
delightful yet irrelevant side branch of our family tree, but what if they are
more representative of our primate background than the blustering chimpanzee?

The assumption that we are born killers
has been challenged from an entirely different angle by paleontologists
asserting that the evidence for warfare does not go back much further than the
agricultural revolution, about 15,000 years ago. No evidence for large-scale
conflict, such as mass graves with embedded weapons, have been found from
before this time. Even the walls of Jericho—considered one of the first
signs of warfare and famous for having come tumbling down in the Old Testament—may
have served mainly as protection against mudflows. There are even suggestions
that before this time, about 70,000 years ago, our lineage was at the edge of
extinction, living in scattered small bands with a global population of just a
couple of thousand. These are hardly the sort of conditions that promote
continuous warfare.

The
once-popular killer ape theory is crumbling under its own lack of evidence,
with "Ardi" putting the last nail in its coffin. On the other side of
the equation, the one concerning our prosocial tendencies, the move has been
towards increasing evidence for humans as cooperative and empathic. Some of
this evidence comes from the new field of behavioral economics with studies
showing that people do not always adhere to the profit principle. We care about
fairness and justice and sometimes let these concerns override the desire to
make as much money as possible. All over the world, people have played the
"ultimatum game," in which one party is asked to react to the
division of benefits proposed by another. Even people who have never heard of the
French enlightenment and its call for ˇgalitˇ
refuse to play along if the split seems unfair. They may accept a split of 60
for the proposer and 40 for themselves, but not a 80 to 20 split. They thus
forgo income that they could have taken, which is something no rational being
should ever do. A small income trumps no income at all.

Similarly, if one gives two monkeys
hugely different rewards for the same task, the one who gets the short end of
the stick refuses to cooperate. We hold out a piece of cucumber, which normally
entices any monkey to perform, but with its neighbor munching on grapes
cucumber is simply not good enough anymore. They protest the situation,
sometimes even flinging those measly cucumber slices away, showing that even
monkeys compare what they get with what others are getting.

And then there is the evidence for
helping behavior, such as the consolation of distressed group members, which
primates do by means of embracing and kissing. Elephants give reassuring
rumbles to distressed youngsters, dolphins lift sick individuals to the surface
where they can breathe, and almost every dog owner has stories of concerned
reactions by their pets. In Roseville, Calif., a black Labrador jumped in front
of his friend, a six-year-old boy, who was being threatened by a rattle snake.
The dog took so much venom that he required blood transfusions to be saved.

The empathy literature on animals is
growing fast, and is no longer restricted to such anecdotes. There are now
systematic studies, and even experiments that show that we are not the only
caring species. At the same time, we are getting used to findings of remarkable
human empathy, such as those by neuroscientists that reward centers in the
brain light up when we give to charity (hence the saying that "doing good
feels good") or that seeing another in pain activates the same brain areas
as when we are in pain ourselves. Obviously, we are hard-wired to be in tune
with the emotions of others, a capacity that evolution should never have
favored if exploitation of others were all that mattered.

Frans
de Waal, a professor of primate behavior in the psychology department at Emory
University, is the author of "The Age of Empathy."